Nuclear power - China tests nuclear power plant, where the core cannot melt
At a conventional nuclear power plant, the "most significant assumed accident," GAU, is a nuclear meltdown. A state where processes in the core can no longer be controlled, and it continues to heat up, eventually melting through the bottom of the reactor.
For the first time, a reactor type was tested in Shandong, China, where this cannot occur. A spherical reactor loses temperature passively when disturbed and does not require an emergency cooling system. In Fukushima, Japan, both standard and backup power supplies failed in 2011, leading to the melting of the core.
The concept is not new, nor is it Chinese. The Chinese have, however, built the first reactor of this design. In Germany, research was conducted on prototypes. In Shandong, on the other hand, a full-scale nuclear power plant, which began operation in December 2023, stands. The Shidaowan Nuclear Power Plant is the first nuclear power plant of the fourth generation.
Modular nuclear power plant
The plant consists of two small reactors, each with a thermal power of 250 Megawatt, which each drive a single steam turbine with an electrical power of 210 Megawatt. A standard nuclear power plant produces 1200 Megawatts, the Chinese type is modular. Additional modules increase power output. Helium is used as a coolant, and graphite as a moderator. Each reactor is equipped with over 400,000 spherical fuel elements, each containing seven grams of fuel. The spheres remain intact at temperatures up to 1620 degrees – significantly higher temperatures than even in extreme emergency situations, according to the China Nuclear Energy Association. The reactor generates both steam up to 500 degrees Celsius and electricity. This is intended to replace the burning of natural gas and coal in the petrochemical industry.
To test the new power plant in an emergency situation, both modules of the reactor were shut down while in operation. The temperature in the plant then decreased naturally. Thirty-five hours after the power supply was cut off, a stable temperature was reached. The test was conducted in 2023. The accompanying study was published in the scientific journal "Joule" recently.
Source: Joule
Despite the success of the modular nuclear power plant in Shandong, a stark reminder of the potential dangers of nuclear power was seen in Fukushima, where an atomic accident led to a melted core at the nuclear power plant, causing significant damage. Although the Shandong plant's design allows for passive cooling and temperature control, avoiding a melted core like the one in Fukushima, it's crucial to continually advance science & technology in nuclear power safety measures, learning from past incidents like Fukushima's nuclear power plant disaster in 2011.
